From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36567C433EF for ; Wed, 15 Jun 2022 00:15:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231879AbiFOAPL (ORCPT ); Tue, 14 Jun 2022 20:15:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232346AbiFOAPJ (ORCPT ); Tue, 14 Jun 2022 20:15:09 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C71C165B7 for ; Tue, 14 Jun 2022 17:15:08 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 03832B81A43 for ; Wed, 15 Jun 2022 00:15:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E0260C3411B; Wed, 15 Jun 2022 00:15:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1655252105; bh=LfCiE7qgiZADY1Mde+IjGpeUSu96x0YdUumS3KY1hQw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=C34/RFCJRcF4KQ9bOmfnYRxEqyUNjHmEHbL3ravUCL8NBWnpXHtSvH/XpWPLfoiCJ E9ScC2nS9Q9DRN0+/Il7BZa7pbvlseRpcl7FVVBqsTtiqh9P+F36/I8FbOe7IqWr0q S8t4IUx+IGrh8kdGVcZmuMzI4FzkhHesA/ROQnJDR4jt4F7u1qxlSxxku9P7SOCeat Fl9Mj2SFS8xDrxeY22/7clBg4sPJRbUndFyuHgtMT4yjOgS2GJbl09jTNMIsGSISr5 nQp6mBZMxl7MpY+IIVFyrApjG9mL1lHqzuAAUseNgPYY+obvqsrHaoqy8ctPtH6Rg9 JkNeM2+XnqFSw== Date: Wed, 15 Jun 2022 09:15:01 +0900 From: Masami Hiramatsu (Google) To: l3b2w1@gmail.com Cc: naveen.n.rao@linux.ibm.com, anil.s.keshavamurthy@intel.com, davem@davemloft.net, linux-kernel@vger.kernel.org, Steven Rostedt Subject: Re: [PATCH] kprobes: drop the unnecessary unlikely() Message-Id: <20220615091501.0323c2c7cc89b2d337cb0322@kernel.org> In-Reply-To: <20220613042536.20329-1-l3b2w1@gmail.com> References: <20220613042536.20329-1-l3b2w1@gmail.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 13 Jun 2022 12:25:36 +0800 l3b2w1@gmail.com wrote: > From: "binglei.wang" > > !ap is likely when checking re-registering existing kprobe. > register_kprobe -> warn_kprobe_rereg -> __get_valid_kprobe > > !ap is unlikely when checking whether the kprobe is valid > on enable/disable ocassion. > __disable_kprobe/enable_kprobe -> __get_valid_kprobe > > Considering these two cases, choose to drop the unlikely() here. > > Signed-off-by: binglei.wang This looks good to me. Acked-by: Masami Hiramatsu (Google) Thank you! > --- > kernel/kprobes.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index f214f8c08..f4a829d98 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -1504,7 +1504,7 @@ static struct kprobe *__get_valid_kprobe(struct kprobe *p) > lockdep_assert_held(&kprobe_mutex); > > ap = get_kprobe(p->addr); > - if (unlikely(!ap)) > + if (!ap) > return NULL; > > if (p != ap) { > -- > 2.27.0 > -- Masami Hiramatsu (Google)